Research on the performance of alkali-activated cement mortars mixed with seawater

In order to study the performance of alkali-activated cement concrete mixed with seawater, long term mechanical tests, carbonation resistance tests and steel corrosion tests of seawater mixed alkali-activated mortars and tap mixed ordinary Portland mortars were assessed under wet and dry cycling conditions. The experimental results showed that the steel in seawater mixing alkali-activated mortars had more extend corrosion in the early age, with the extension of age, the corrosion rate grew slowly compared to that of the Portland cement mortars, after 30 cycles, the gravity loss rate of steel was 1.2%, which was 1/3 of that of the Portland cement mortars. The strength of alkali-activate mortars increased progressively, the compressive strength at 7 months increased by 96% as to 28 d age, and the past became higher density. After 10 months of wet and dry cycling, the carbonation depth of alkali-activate mortars was 5.8 mm, and there was no significant difference to Portland mortars. XRD, MIP and other analysis were used to explore the superior performance mechanism of alkali-activate cement. It is indicated that alkali-activate cement could be used for preparing marine concrete, or even mixing with seawater directly.